There are renewable heat sources: geothermal, solar heating, solar furnaces [if you need temperatures in the thousands of Kelvin). There are renewable [carbon-neutral] fuels: biomass, wood, ethanol...
Heat-intensive industries will be limited by the amount of renewable heat that can be farmed.
A separate argument is that a fuel is too precious (in its energy density and its mobility) to burn it in a static industrial plant. The opportunity cost is too large. I don't have a problem with using renewable electricity for a heat-intensive industry, the opportunity cost is less, especially if the power comes from an attach power facility (solar panels, wind farm, sharing the location of the industrial plant; building the industrial plant on a geothermal hot spot, near a tidal power generator...).
That os my opinion anyway. It's not backed by any actual calculations, back-of-the-envelope or not. guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper
...as you have given me another opportunity to push trains... *Lunatic*, n. One whose delusions are out of fashion.
